This is a categorized and annotated directory of available Clojure libraries and tools. This directory is not comprehensive and is necessarily highly opinionated.

This directory is manually curated by the Clojure community. Please endeavor to keep it up-to-date, consisting of high quality libraries with adequate documentation. There are many more libraries in the Clojure ecosystem, but some lack documentation and/or are useful primarily to experienced developers and such projects are not included in this document.

For more comprehensive overview of the Clojure library ecosystem, please see ClojureSphere.

Support Libraries

General

• useful (at clojars)

• ClojureWerkz Support (at clojars)

• medley (at clojars)

Applications & Environment

• tools.cli: a command line argument parser for Clojure

• environ: Manage environment settings from a number of different sources

• carica (at clojars): Flexible config file usage & management library.

Date and Time

• clj-time: A date and time library for Clojure

Testing

• clojure.test: the standard unit testing library that ships with Clojure

• Midje: a more featureful test framework

• cloverage: a test-coverage tool (lein plug-in)

• expectations (at clojars): a minimalist's testing framework

• test.generative: generative testing, a la QuickCheck

• conjure (at clojars): mocking and stubbing for unit tests.

Namespaces and Code-as-Data

• tools.namespace

• builtitude (at clojars)

• findfn (at clojars)

• ns-tracker (at clojars)

Serialization

JSON

• cheshire (at clojars): very efficient Clojure JSON and SMILE (binary JSON) encoding/decoding.

• data.json: JSON parser/generator to/from Clojure data structures.

Protocol Buffers

• clojure-protobuf (at clojars): a Clojure interface to Google's protocol buffers

Kryo

• carbonite

Clojure Reader

• Nippy (at clojars): a more efficient implementation of the Clojure reader

XML

• data.xml: a library for reading and writing XML

Binary Formats

• gloss (at clojars): turns complicated byte formats into Clojure data structures

File formats

• clj-pdf: a library for easily generating PDFs from Clojure

• Pantomime (at clojars): a tiny Clojure library that deals with Internet media types (MIME types) and content type detection

• data.csv: a CSV parser

Templating

• Stencil: Mustache for Clojure (logic-less templates). Fast.

• Clostache: another nice Mustache implementation

HTTP

Client/Server

• HTTP Kit (at clojars): High-performance event-driven HTTP client/server for Clojure.

Client

• clj-http (at clojars): An idiomatic Clojure http client wrapping the apache client.

• clj-http-lite (at clojars): A lightweight version of clj-http having almost same API, but without any Apache dependencies.

Logging

• Timbre: Simple, flexible, all-Clojure logging. No XML!

• tools.logging: standard general-purpose logging.

• clj-log: s-expression logger.

Web Development

Web Services

• Ring (at clojars): foundational web application library

• Compojure (at clojars): concise routing library for Ring

• Pedestal (at clojars): an open source tool set for building web applications in Clojure

• Luminus: lein template for creating batteries-included web applications using Ring, Compojure, lib-noir, and other libraries.

• Liberator (at clojars): a Clojure library for building RESTful applications

• friend (at clojars): Authentication and authorization library for Web apps

HTML Generation

• hiccup: Generates HTML from Clojure data structures.

• Stencil: Implements the Mustache templating language.

• markdown-clj: Clojure based Markdown parsers for both Clojure and ClojureScript.

HTML Parsers

• Crouton: A Clojure wrapper for the JSoup HTML and XML parser that handles real world inputs

• Crawlista (at clojars): a support library for applications that crawl the Web

• TagSoup: a tool for parsing html as it's found in the wild: poor, nasty, and brutish.

Data Validation

• Validateur (at clojars): functional validations library inspired by Ruby's ActiveModel

• Metis: another validations library inspired by Ruby's ActiveModel

• Clj-Schema (at clojars): Schemas for Clojure Data: validation and test data generators

URIs, URLs

• Urly (at clojars): unifies java.net.URL, java.net.URI and string URIs, provides parsing and manipulation helpers

• Exploding Fish (at clojars): a URI library for Clojure

• route-one (at clojars): a tiny Clojure library that generates HTTP resource routes (as in Ruby on Rails, Jersey, and so on)

Internationalization (i18n), Localization (l10n)

• Tower (at clojars): a simple, idiomatic internationalization and localization story for Clojure

RSS

• clj-rss: RSS feed generation library

Data Stores

Relational Databases, JDBC

• java.jdbc: Basic wrapper for JDBC. Works with all JDBC databases (MySQL, PostgreSQL, Oracle, SQL Server, etc).

• Korma: "Tasty SQL for Clojure"

CouchDB

• Clutch (at clojars): Apache CouchDB client.

MongoDB

• Monger (at clojars): Monger is an idiomatic Clojure MongoDB driver for a more civilized age with solid documentation

• congomongo (at clojars): Basic wrapper for the MongoDB Java driver

• Mongoika (at clojars)

Riak

• Welle (at clojars): An expressive Clojure client for Riak with solid documentation

Redis

• Carmine (at clojars): a great Clojure client for Redis

Graph Databases (Neo4J, Titan, etc)

• Neocons (at clojars): Neocons is a feature rich idiomatic Clojure client for the Neo4J REST API with solid documentation

• Titanium (at clojars): a Clojure graph library built on top of Titan

• Archimedes (at clojars): a Clojure wrapper for Tinkerpop Blueprints

• Ogre (at clojars): a Clojure library for querying Tinkerpop graphs

• Borneo (at clojars)

ElasticSearch

• Elastisch (at clojars): Elastisch is a minimalistic Clojure client for ElasticSearch with solid documentation.

• Esperanto

Memcached, Couchbase, Kestrel

• Spyglass (at clojars): Spyglass is a very fast Clojure client for Memcached and Couchbase with solid documentation

Apache Cassandra

• Cassaforte (at clojars): A young Clojure client for Apache Cassandra

• clj-hector (at clojars): A simple Clojure client for Cassandra that wraps Hector

• Alia (at clojars): Cassandra CQL3 client for Clojure, datastax/java-driver wrapper

• ccm-clj (at clojars: Clojure interface to the Cassandra Cluster Manager, ccm

Amazon DynamoDB

• Rotary (at clojars)

Tokyo Cabinet

• tokyocabinet (at clojars): native Tokyo Cabinet interface for Clojure

Misc

• masai (at clojars): a very simple interface to a number of key-value stores

• jiraph (at clojars): a reasonably licensed embedded graph database with swappable backends

Networking

• Lamina (at clojars): event-driven workflows in Clojure

• Aleph (at clojars): asynchronous communication in Clojure

Application Servers

• Immutant (at clojars): a feature rich and integrated application platform for Clojure from Red Hat

Messaging

RabbitMQ

• Langohr (at clojars): a feature complete RabbitMQ client that embraces AMQP 0.9.1 model and learns from others

ZeroMQ

• Jilch (at clojars): Clojure ZeroMQ Library using JeroMQ, no native dependencies

Beanstalk

• beanstalk (at clojars): a Beanstalkd client

Amazon SQS

• Bandalore: a Clojure client library for Amazon's Simple Queue Service

HornetQ

• hornetq-clj (at clojars): a tiny HornetQ client

Data Processing, Computation

• Twitter Storm (at clojars): distributed realtime computation system

• Cascalog (at clojars): data processing on Hadoop without the hassle

Natural Language Processing

• clojure-opennlp (at clojars)

Parsers, Parser Combinators, Language Construction

• Instaparse (at clojars)

• Kern (at clojars)

Automation, Provisioning, DevOps Tools

• pallet (at clojars): a platform for agile and programmatic automation of infrastructure

• jclouds: unified APIs for dozens of cloud (IaaS) providers

• Amazonica: comprehensive Clojure client for the entire AWS API

• clj-ssh (at clojars): an SSH client

• ssh-transport: executes commands over SSH

Monitoring, metrics

• metrics-clojure (at clojars): Clojure library on top of Yammer's Metrics

• clj-statsd (at clojars): simple client library to interface with statsd

• pulse: Real-time Heroku operations dashboard

• riemann (at clojars): A network event stream processing system, in Clojure.

I/O

Files, NIO, NIO2

File I/O is covered by the JDK and commonly used via clojure.java.io functions.

• fs (at clojars): utilities for working with the file system
• nio: Clojure library for working with for Java NIO classes

Standard Streams, Subprocesses

Standard streams I/O is covered by the JDK and commonly used via clojure.java.io functions.

• clojure.java.shell (part of Clojure distribution): Conveniently launch a sub-process providing its stdin and collecting its stdout.

• conch: for shelling out to external programs. An alternative to clojure.java.shell.

Property Files

• propertea (at clojars): painlessly work with property files

REPL and Terminal

• REPLy (at clojars): a Swiss army knife of interactive editing, and better REPL for Clojure

• clojure-lanterna (at clojars): for creating TUIs (terminal-based user-interfaces), like ncurses.

Concurrency and Parallelism

• java.util.concurrent: a comprehensive, very mature set of concurrency primitives built into the JDK
• Okku (at clojars): Akka API for Clojure

Mathematics

• math.numeric-tower: various utility math functions

• math.combinatorics: common combinatorial functions

• core.matrix: matrix operations

Email

• Postal (at clojars): generate and send email with Clojure

• Mailer (at clojars): generate and send email using Postal and Moustache templates

Data Structures and Algorithms

Strings

• clojure.string

Sets

• clojure.set

Caching

• core.cache: the Clojure API for various cache implementations

UUIDs

• tardis (at clojars): manages Type 1 UUIDs (time based)

Monads

• algo.monads: macros for defining monads, and definition of the most common monads

• protocol-monads: A protocol based monad implementation for clojure

Memoization

• core.memoize

Other

• vclock (at clojars): a vector clocks implementation

• chash (at clojars): a consistent hashing library

Scheduling

• Quartzite (at clojars): a powerful scheduling library

Graphics and GUI

• Quil: For making drawings, animations, and artwork (some examples). Wraps the "Processing" graphics environment.

• seesaw (at clojars): A Swing wrapper/DSL.

• clisk: Clisk is a DSL-based library for procedural image generation that can be used from Clojure and Java.

Security and Sandboxing

• Clojail (at clojars): a [code execution] sandboxing library

Documentation

Literate Programming

• Marginalia (at clojars): literate programming implementation for Clojure. See the Marginalia site for an example.

• Marginalia Leiningen plug-in (at clojars)

Generating API Reference

• Codox (at clojars): from the author of Compojure. See compojure api docs for an example.

• Autodoc (at clojars): used to generate the official Clojure API reference.

Tooling

• Leiningen: the Clojure build tool

• tools.nrepl: nREPL interface

• java.jmx: nice JMX interface

• test.benchmark: a benchmarking library

• tools.trace: a tracing library

• criterium (at clojars): a benchmarking library that tries to address common benchmarking pitfalls

• print-foo (at clojars): A library of print debugging macros.

• gui-diff (at clojars): Tools for side-by-side diffing of Clojure data structures and clojure.test failures